handleQueryStream refactor

packages/api/src/utility/handleQueryStream.js

@@ -0,0 +1,169 @@
+const crypto = require('crypto');
+const path = require('path');
+const fs = require('fs');
+const _ = require('lodash');
+
+const { jsldir } = require('../utility/directories');
+
+class QueryStreamTableWriter {
+  constructor() {
+    this.currentRowCount = 0;
+    this.currentChangeIndex = 1;
+    this.initializedFile = false;
+  }
+
+  initializeFromQuery(structure, resultIndex) {
+    this.jslid = crypto.randomUUID();
+    this.currentFile = path.join(jsldir(), `${this.jslid}.jsonl`);
+    fs.writeFileSync(
+      this.currentFile,
+      JSON.stringify({
+        ...structure,
+        __isStreamHeader: true,
+      }) + '\n'
+    );
+    this.currentStream = fs.createWriteStream(this.currentFile, { flags: 'a' });
+    this.writeCurrentStats(false, false);
+    this.resultIndex = resultIndex;
+    this.initializedFile = true;
+    process.send({ msgtype: 'recordset', jslid: this.jslid, resultIndex });
+  }
+
+  initializeFromReader(jslid) {
+    this.jslid = jslid;
+    this.currentFile = path.join(jsldir(), `${this.jslid}.jsonl`);
+    this.writeCurrentStats(false, false);
+  }
+
+  row(row) {
+    // console.log('ACCEPT ROW', row);
+    this.currentStream.write(JSON.stringify(row) + '\n');
+    this.currentRowCount += 1;
+
+    if (!this.plannedStats) {
+      this.plannedStats = true;
+      process.nextTick(() => {
+        if (this.currentStream) this.currentStream.uncork();
+        process.nextTick(() => this.writeCurrentStats(false, true));
+        this.plannedStats = false;
+      });
+    }
+  }
+
+  rowFromReader(row) {
+    if (!this.initializedFile) {
+      process.send({ msgtype: 'initializeFile', jslid: this.jslid });
+      this.initializedFile = true;
+
+      fs.writeFileSync(this.currentFile, JSON.stringify(row) + '\n');
+      this.currentStream = fs.createWriteStream(this.currentFile, { flags: 'a' });
+      this.writeCurrentStats(false, false);
+      this.initializedFile = true;
+      return;
+    }
+
+    this.row(row);
+  }
+
+  writeCurrentStats(isFinished = false, emitEvent = false) {
+    const stats = {
+      rowCount: this.currentRowCount,
+      changeIndex: this.currentChangeIndex,
+      isFinished,
+      jslid: this.jslid,
+    };
+    fs.writeFileSync(`${this.currentFile}.stats`, JSON.stringify(stats));
+    this.currentChangeIndex += 1;
+    if (emitEvent) {
+      process.send({ msgtype: 'stats', ...stats });
+    }
+  }
+
+  close(afterClose) {
+    if (this.currentStream) {
+      this.currentStream.end(() => {
+        this.writeCurrentStats(true, true);
+        if (afterClose) afterClose();
+      });
+    }
+  }
+}
+
+class StreamHandler {
+  constructor(resultIndexHolder, resolve, startLine) {
+    this.recordset = this.recordset.bind(this);
+    this.startLine = startLine;
+    this.row = this.row.bind(this);
+    // this.error = this.error.bind(this);
+    this.done = this.done.bind(this);
+    this.info = this.info.bind(this);
+
+    // use this for cancelling - not implemented
+    // this.stream = null;
+
+    this.plannedStats = false;
+    this.resultIndexHolder = resultIndexHolder;
+    this.resolve = resolve;
+    // currentHandlers = [...currentHandlers, this];
+  }
+
+  closeCurrentWriter() {
+    if (this.currentWriter) {
+      this.currentWriter.close();
+      this.currentWriter = null;
+    }
+  }
+
+  recordset(columns) {
+    this.closeCurrentWriter();
+    this.currentWriter = new QueryStreamTableWriter();
+    this.currentWriter.initializeFromQuery(
+      Array.isArray(columns) ? { columns } : columns,
+      this.resultIndexHolder.value
+    );
+    this.resultIndexHolder.value += 1;
+
+    // this.writeCurrentStats();
+
+    // this.onRow = _.throttle((jslid) => {
+    //   if (jslid == this.jslid) {
+    //     this.writeCurrentStats(false, true);
+    //   }
+    // }, 500);
+  }
+  row(row) {
+    if (this.currentWriter) this.currentWriter.row(row);
+    else if (row.message) process.send({ msgtype: 'info', info: { message: row.message } });
+    // this.onRow(this.jslid);
+  }
+  // error(error) {
+  //   process.send({ msgtype: 'error', error });
+  // }
+  done(result) {
+    this.closeCurrentWriter();
+    // currentHandlers = currentHandlers.filter((x) => x != this);
+    this.resolve();
+  }
+  info(info) {
+    if (info && info.line != null) {
+      info = {
+        ...info,
+        line: this.startLine + info.line,
+      };
+    }
+    process.send({ msgtype: 'info', info });
+  }
+}
+
+function handleQueryStream(dbhan, driver, resultIndexHolder, sqlItem) {
+  return new Promise((resolve, reject) => {
+    const start = sqlItem.trimStart || sqlItem.start;
+    const handler = new StreamHandler(resultIndexHolder, resolve, start && start.line);
+    driver.stream(dbhan, sqlItem.text, handler);
+  });
+}
+
+module.exports = {
+  handleQueryStream,
+  QueryStreamTableWriter,
+};